CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect Period Of Adoption Adjustment [Member]	Class A and B Common Stock [Member]	Additional Paid-in Capital [Member]	Purchase Price Of Excess Of Predecessor Basis, Net Of Tax [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect Period Of Adoption Adjustment [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]
Beginning Balance at Dec. 31, 2018	$ 980,834		$ 419	$ 172,220	$ (15,458)	$ 1,072,456		$ (182)	$ (248,621)
Beginning Balance (in shares) at Dec. 31, 2018			41,887,088						(7,431,083)
Accounting Standards Update [Extensible List]		ASU No. 2016-02 [Member]					ASU No. 2016-02 [Member]
Purchase of treasury shares	(24,998)								$ (24,998)
Purchase of treasury shares (in shares)									(626,320)
Stock tendered for payments of withholding taxes	(3,984)								$ (3,984)
Stock tendered for payments of withholding taxes (in shares)									(98,260)
Issuance of restricted stock awards, net of forfeitures				(8,869)					$ 8,869
Issuance of restricted stock awards, net of forfeitures (in shares)									284,775
Share-based compensation expense	16,286			16,286
Net income	107,171					107,171
Foreign currency translation adjustment	(4)							(4)
Ending Balance at Dec. 31, 2019	1,075,279	$ (26)	$ 419	179,637	(15,458)	1,179,601	$ (26)	(186)	$ (268,734)
Ending Balance (in shares) at Dec. 31, 2019			41,887,088						(7,870,888)
Stock tendered for payments of withholding taxes	(7,963)								$ (7,963)
Stock tendered for payments of withholding taxes (in shares)									(148,242)
Issuance of restricted stock awards, net of forfeitures				(10,632)					$ 10,632
Issuance of restricted stock awards, net of forfeitures (in shares)									344,046
Share-based compensation expense	17,053			17,053
Net income	73,559					73,559
Foreign currency translation adjustment	(5)							(5)
Ending Balance at Dec. 31, 2020	$ 1,157,923		$ 419	186,058	(15,458)	1,253,160		(191)	$ (266,065)
Ending Balance (in shares) at Dec. 31, 2020			41,887,088						(7,675,084)
Purchase of treasury shares (in shares)	134,329
Stock tendered for payments of withholding taxes	$ (9,123)								$ 9,123
Stock tendered for payments of withholding taxes (in shares)									(134,329)
Issuance of restricted stock awards, net of forfeitures				(16,858)					$ 16,858
Issuance of restricted stock awards, net of forfeitures (in shares)									492,355
Share-based compensation expense	20,056			20,056
Net income	171,474					171,474
Foreign currency translation adjustment	(16)							(16)
Ending Balance at Dec. 31, 2021	$ 1,340,314		$ 419	$ 189,256	$ (15,458)	$ 1,424,634		$ (207)	$ (258,330)
Ending Balance (in shares) at Dec. 31, 2021			41,887,088						(7,317,058)